Breaking News: Kepler Team Spots First Earth-Sized Exoplanets

The video above sums up the big astro-news of the day: NASA’s Kepler mission has confirmed the existence of not one but TWO Earth-sized planets orbiting a Sun-like star 1,000 light-years away. This is a big deal!

Earlier this month the team announced the discovery of Kepler-22b, an exoplanet orbiting its star well within its habitable zone – the region where liquid water can exist without boiling off or freezing altogether.
But Kepler-22b is nearly 2 1/2 times the size of Earth and is suspected to be less dense, leading researchers to believe it may have a thick atmosphere and a surface not conducive to liquid water and/or life. (More study is still needed on that though.)
Artist's concept of Kepler-20f, a rocky planet 1.03 times the radius of Earth. Credit: NASA/Ames/JPL-Caltech
These newly-announced exoplanets, designated Kepler-20e and -20f, are much nearer to Earth size BUT orbit their star too closely to be habitable. So although they are truly Earth-sized exoplanets they can’t be called “Earthlike”, not with temperatures at or above the 1000-degree F mark.
Still, this is the first time that small rocky worlds orbiting other stars have been confirmed… it’s one more step toward that all-important discovery ...